When a television is initially installed in a user's home after purchase, the receivers of the TV search for what channels are available in the area. In conventional analog television sets such automatic search and tuning (referred to as “autoprogramming”) might take only a few seconds. Upon completion of the search, the television possesses a channel map that indicates which frequencies/channels are available for subsequent tuning when a user selects a channel.
However, with the advent of digital televisions and hundreds of satellite channels, digital ones of which might in fact carry several sub-channels, the autoprogramming function discussed above can consume an inordinate amount of time. This is not only because of the increased number of channels but also because digital channels are more complicated to map, requiring not just a frequency map but also various decoding information. Furthermore, even with algorithmic efforts to speed up the autoprogram process, much time is still required and because some broadcasts are not available 24 hours per day, some channels can be missed. In the case of terrestrial broadcast the orientation of the antenna can also affect reception to the point where some otherwise available channels might not be detected.